1. Field of the Invention
The present invention relates to a headgear frame apparatus of a sewing machine for embroidering a headgear.
2. Description of the Related Art
As shown in FIGS. 10 and 11, a first conventional headgear frame apparatus 105 is provided with: a headgear frame 100 for clamping a headgear 1; a rotary drive frame 106 for fitting said headgear frame 100 replaceably thereon on the side of a sewing machine; a support frame 109 for supporting said rotary drive frame 106 rotatably; and a guide plate 110 fixed on said support frame 109 and extending to the side of a cylindrical bed 111 of the sewing machine.
When the support frame 109 is to be mounted on the sewing machine, a mounting bracket 113 is fixed on the upper face of a horizontal drive frame (or a pantograph) 112. On the back face of the bracket 113, there is mounted a rotary drive slide rail 114 having a rail groove 114a, in which the support frame 109 is fitted through bearing rollers 115.
According to this structure, however, the support frame 109 can be easily mounted, but a clearance 116 is necessarily required between the rail groove 114a and the bearing rollers 115. This clearance 116 leaves a longitudinal looseness to affect the embroidery adversely. At a high speed (e.g., 750 rpm), moreover, the headgear frame 100 oscillates vertically to break the needle frequently or to blot the finish of the embroidery.
As shown in FIG. 12, on the other hand, a second conventional headgear frame apparatus 150 is provided with: a guide rail 151a projected below the root and end portion of a cylindrical bed 151 in parallel with the cylindrical bed 151; a support frame 153 supported slidably along said guide rail 151a and rotatably supporting a rotary drive frame 152 fitting the (not-shown) headgear frame replaceably thereon for clamping the headgear; a transmission mechanism 154 for transmitting a driving force to the rotary drive frame 152; and a horizontal drive frame 155 for driving the rotary drive frame 152 longitudinally through the support frame 153 and for driving the rotary drive frame 152 rotationally through the transmission mechanism 154.
The support frame 153 is composed of a front side member 153a positioned on the front side of the horizontal drive frame 155, and a back side member 153b positioned on the back side of the horizontal drive frame 155. The back side member 153b is jointed to the front side member 153a through joint screws 153c.
By loosening the joint screws 153c to remove the back side member 153b from the front side member 153a and by removing a joint member 156 joining the transmission mechanism 154 and the horizontal drive frame 155, moreover, the support frame 153, the rotary drive frame 152 and the transmission mechanism 154 can be removed from the horizontal drive frame 155.
The transmission mechanism 154 is provided with a base member 157 joined to the horizontal drive frame 155 by the joint member 156 and extending transversely, and a wire 158 wound by one turn on the circumferential wall of the rotary drive frame 152 and fixed at both end portions, individually, on the left and right end portions of the base member 157. The wire 158 is fixed at its generally intermediate portion on the circumference wall of the lower end side of the rotary drive frame 152 through a clamping member 159 so that when the horizontal drive frame 155 is moved transversely, the rotation is applied to the rotary drive frame 152 through the wire 158.
In order to transport the sewing machine, to replace the headgear frame apparatus 150 by a holding frame for working a cylindrical cloth other than the headgear or to replace the headgear frame apparatus 150 suitably according to the headgear 1, this headgear frame apparatus 150 is constructed such that when the joint member 156 is removed, the support frame 153, the rotary drive frame 152 and the transmission mechanism 154 can be removed from the horizontal drive frame 155.
After these removals, however, there arises a problem that the base member 157 of the transmission mechanism 154 is brought into an unstable state where it is connected to the rotary drive frame 152 through the wire 158.